In the automotive field, the operation of major original equipment manufacturer (OEM) subsystems, such as the engine, emissions, transmission, and braking has become computerized, as have convenience-type features such as power locks, windows, sliding doors, and the like. Since these OEM subsystems are now usually controlled, either entirely or in part, by an OEM controller including a microcomputer, the vehicle may include a number of sensors that communicate with the OEM controller. Further, the microcomputer may additionally be programmed with software to operate various safety features in response to outputs from the sensors. For example, most modern vehicles are operative to sense when a driver is wearing a safety belt. If the driver does not employ their safety belt, the vehicle may provide a warning such as a visual indication (e.g., dashboard light or message), an audible indication (e.g., chime or warning sound), or other indication to notify and/or remind the noncompliant driver of the unsafe condition.
In another example, vehicles may also sense when one or more doors are open or ajar to prevent an occupant from accidentally falling out of the vehicle when it is in motion. In some instances, if an open door condition is detected by a door sensor, the OEM vehicle controller may operate to prevent the driver from shifting the stationary vehicle out of park or neutral. With ongoing attempts to make passenger vehicles safer, air bags are employed to prevent occupant injury during collisions. To this end and in a further example, crash sensors operate in a vehicle to detect the instance of a collision and communicate the crash occurrence to the OEM vehicle controller so that the controller may output a signal to deploy one or more air bags. Moreover, with the increasing availability of telematics (e.g., OnStar®), many vehicles are operative to automatically notify emergency services of a vehicle collision almost immediately upon the signal output of a crash sensor.
To comply with the Americans with Disabilities Act (ADA), many public and private vehicles are being equipped with auxiliary devices such as wheelchair lifts and ramps. Such auxiliary devices provide access to vehicles such as vans, busses, minivans and the like for mobility-challenged persons. Control systems for the foregoing auxiliary devices have generally relied on the assistance of the auxiliary device operators (often the vehicle driver). Unfortunately, such auxiliary device control systems have proven to be generally deficient in providing an adequate level of safety to an auxiliary device user.
Several factors have been identified which contribute to operator error: (1) the lack of familiarity with the controls, (2) the lack of standardization in the control sequence and types of controls (e.g., different controls for different lifts), and (3) the lack of operator training. In addition, even though the user of the auxiliary device may be fully visible to the operator, the operator may not be aware of the passenger's presence. This “looked but did not see” or daydreaming phenomenon is a frequent cause of motor vehicle collisions. For example, the National Highway Transportation Safety Administration (NHTSA) Office of Defects Investigation (ODI) has reported cases in which accidents occurred on vehicle wheelchair lifts when an operator accidentally tried to stow a lift with the user still on the lift platform. To this end, the NHTSA has proposed safety features known in the art as “interlocks” that are expected to help prevent the auxiliary device operator from making errors.
Additionally, lack of routine system maintenance has been cited as a cause of malfunctions of auxiliary devices. To this end, the NHTSA has proposed an “operations counter” that records each complete (i.e., through its entire range of motion) operation of the auxiliary device. The operations counter, which may provide an operator or technician with a general indication of the device's usage and/or age, is only helpful in assisting with identification of an appropriate maintenance task (e.g., preventative maintenance procedure) to be performed. For example, the auxiliary device's hydraulic system should be inspected after a predetermined number (e.g., 100) of uses.
To improve auxiliary device safety, auxiliary device controls are becoming less operator-assisted and more computerized and automated. Moreover, to enhance the safety of vehicles with installed auxiliary devices, it would be advantageous to facilitate communications between the auxiliary device's control system and the OEM controller. By communicating in this manner, the auxiliary device control system could operate to communicate with OEM subsystem elements such as sensors, switches, motors, and the like to enable a plurality of safety features and interlocks. In view of the foregoing, there exists a need for an electronic auxiliary device controller that operates to enable safety interlocks through coordination of various OEM and auxiliary subsystems, assists in system diagnostics, and indicates unsafe operating conditions such as when repair or maintenance is required, and the like.